The present invention relates to a tape measure whose measuring strip (blade) is provided at its free end with an end hook that has a projecting front end bent at a right angle to the measuring strip and a coarse surface for abutting the object to be measured.
Usually, the end hook of a tape measure is an L-shaped square hook whose fixed portion is secured to the free end of the measuring strip in such a way as to be movable in a longitudinal direction and whose projecting front end is bent at a right angle thereto. When the tape measure is being used, the end hook is abutted at its front (outside) or rear (inside) surface against a flat surface or edge of the object to be measured.
For example, in the case of measuring the inside width of a window opening it is necessary to abut the front surface of the end hook of the tape measure against the inner wall of the window's opening.
On the other hand, in the case for determining the width or length of a table plate, the end hook of the tape measure is hooked at its rear surface on the edge of the table plate and the measuring strip is drawn from a case along the table top. In this case the hook might slip off the table's edge even if the measuring strip is of a self-sustaining type made of a flexible but stiff material such as steel. In this case, it may be necessary to replace the hook at the table's edge often.
To avoid this, one must hold the end hook of the tape measure by one hand and draw the measuring tape with the other hand when measuring the length of an object that is shorter than an open arm's width. However, if the object's length exceeds the width of an open arm, help is required from another person or the hook must be fixed to the object by the use of a subsidiary means such as a needle, adhesive tape, a magnet and so on.
Conventionally, a variety of fixing means have been devised, for example, to form linear grooves on the abutting surface of the end hook of a tape measure, or to provide a small convexed portion on the under surface of the end hook, or to apply a frictional layer of fine crystal material on the abutting surface of the end hook as disclosed in the Japanese publication of unexamined patent application No. 3-295401.
The above-mentioned proposals, however, have the following drawbacks: the existence of a partial convexity scarcely improves the holding effect and the application of a fine crystal frictional layer to the hook's surface often causes an uneven thickness, thereby decreasing the accuracy of the measuring process and increasing the manufacturing costs.